foo <- function(a, ..., b=1)
	return(a)

bar <- function(a, b=1)
	return(a)

for(i in 1)
	foo(1,2,3,4,5,6)
foo(a=1, b=2, c=3, d=4, e=5, f=6)

42

#bar(1,2,3,4,5,6)
#bar(a=1, b=2, c=3, d=4, e=5, f=6)
